Pan-diatonicism sanctions the simultaneous use of any or all seven tones of the diatonic scale, with the bass determining the harmony. The chord-building remains tertian, with the seventh, ninth, or thirteenth chords being treated as consonances functionally equivalent to the fundamental triad. (The eleventh chord is shunned in tonic harmony because of its quartal connotations.) Pan-diatonicism, as consolidation of tonality, is the favorite technique of NEO-CLASSICISM [sic]. (Slonimsky 1938, xxii)

The term has been criticized as one of many by which, "Stravinsky's music, everywhere and at once, is made to represent or encompass every conceivable technique" (van den Toorn 1975, 105), and that has, "become so vague a concept that it has very little meaning or use" (Woodward 2009, 1). Pandiatonic music is usually defined by what it is not, "by the absence of traditional elements" (Woodward 2009, iii): chromatic, atonal, twelve-tone, functional, clear tonic, and/or traditional dissonance resolutions (Woodward 2009, 3). "It has been applied...to diatonic music lacking harmonic consistency [or]...centricity" (Tymoczko 2011, 188n31). Slonimsky himself, while making fun of the definition, quotes a professor saying pandiatonicism is, "C-major that sounds like hell" (Woodward 2009, 2).